Convertible road and rail wheel assembly

ABSTRACT

A self-propelled four-wheel vehicle ( 1 ) for travel on land and/or on rails includes four hubs ( 9 ) for mounting of wheels including tires ( 6 ) for travel on land, four rail wheels ( 7 ) for travel on a railway, and four coupling assemblies, for detachably connecting the rail wheels to, outwardly of, and spaced from, the hubs. A kit for converting the vehicle for travel on rails includes, for each hub ( 9 ) of the vehicle, a rail wheel adapter ( 25, 44 ) including a flange ( 26, 45 ) for fastening to a rail wheel ( 7 ) and an axle portion ( 24, 46 ) extending transverse to the flange, a vehicle wheel adapter ( 10, 40 ) including a flange ( 15, 41 ) for fastening to a hub of the land vehicle and an axle portion ( 21, 42 ) extending transverse to the flange, and a coupler ( 12, 13 ) for coupling the rail wheel adapter to the vehicle wheel adapter.

This application claims the benefit of U.S. Patent Application60/382,566, filed May 24, 2002, the disclosure of which is incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to vehicles that can travel on both land and on arailroad and to a kit for converting a land vehicle so that the vehiclecan travel both on land and on a railroad.

BACKGROUND OF THE INVENTION

For many years railroads have employed small vehicles for inspectingrailroad tracks and for transporting maintenance crews to locations onrailroad tracks where repair and/or maintenance is needed. Since only afew persons, a section crew, are required to perform many smallmaintenance tasks and inspections, small rail vehicles carrying a fewpersons to remote locations are needed. In most locations only a singlerailroad track is available so that, ideally, the vehicle transportingthe section crew can be easily removed from railroad tracks at the siteof maintenance to allow trains to pass. Likewise, the vehicle should beeasily replaced on the tracks for return of the section crew orinspectors to a central location. Further, it is particularly desirableto enter a rail system at locations remote from central railroad yards.Many remote locations are most easily accessed by traveling on a highwayto an intersection with railroad tracks, i.e., at a grade crossing. Atthe grade crossing the rail vehicle may be placed on the tracks formovement to the location of inspection and/or maintenance.

Historically, a vehicle referred to as a section car has been used totransport section crews. These vehicles are self-propelled vehicles thatcan travel only on railroad tracks. These section cars must be moved toa siding during maintenance to allow a train to pass or must becompletely removed from the track. Various hydraulic devices have beenused to assist crews in removing and replacing section cars on tracks, avery time consuming and inefficient process. Further, the hydraulicdevices increase cost of the cars and their maintenance. Some sectioncars can be removed and replaced on rails manually, but this taskrequires substantial effort by the crew and puts the crew at risk ofinjury.

In recent years, conventional highway vehicles, such as pickup trucksand utility trucks, have been modified to travel both on rails, usingrails wheels, and on highways using the conventional rubber tires of thevehicles. Special rail wheels are fitted to the front and rear of suchvehicles. In general, the rail wheels simply ensure that the vehicleremains on the rails. The vehicle propulsion is provided through therubber tires. The rubber tires may contact the rails or the rail wheels.In these vehicles, it is typically necessary to employ special wheels,altering the distance between tires mounted on an axle of the vehicle.Therefore, a distance that corresponds to the rail gauge, i.e., theseparation between the rails, must separate the rubber tires. In othervehicles altered to travel on both highways and on rails, the propulsionsystem of the vehicle may have to be modified to drive the rail wheels.The modifications are relatively expensive. These vehicles employingboth rubber tires and rail wheels can be placed on rails at gradecrossings. However, substantial time is required to transfer the vehicleto rails since the vehicle must be turned perpendicular to the passageof vehicles on the intersecting highway. In addition, once thesevehicles are at a location remote from a grade crossing, it isdifficult, if not impossible, to remove the vehicle from the rails toallow a train to pass. This difficulty in keeping the track clearinterferes with rail traffic, causing substantial inefficiency inrailroad operations.

Numerous manufacturers make commercially available relatively smallfour-wheel rubber-tired vehicles, referred to as utility vehicles orall-terrain vehicles (ATV). While utility vehicles and ATVs have somesignificant differences, these vehicles all have four wheels, rubbertires, and are self-propelled, for example by an internal combustionengine. Because of these similarities, these vehicles are considered tobe the same for the purposes of the following description. Manufacturersof such vehicles include John Deere, Honda, and Kawasaki. Many of thesevehicles are intended for off-road use, i.e., traveling across openland. The off-road vehicles can, however, travel on public roads ifproperly licensed. The separation between the rubber tires on the frontaxle and on the rear axle of these utility vehicles and ATVs is narrowerthan most rail gauges. The vehicles are relatively lightweight,inexpensive, and readily obtained. Many of the vehicles can transporttwo or more persons as well as some cargo. Since these vehicles canreadily travel across open land and are self-propelled, they arepotentially useful in inspection of railroad track and in transportinginspectors and section crews to remote railroad track locations.However, the vehicles cannot be used directly in a railroad system.

It is known from U.S. Pat. No. 4,744,324 that ATVs can be adapted touses other than land travel by altering the conventional rubber tiresthat are supplied with the vehicle. According to this patent, an ATV canbe converted to an amphibious vehicle by replacing the conventionaltires with balloon tires that function as floatation devices. Inaddition, each of the driven rear wheels of the ATV can have attached toit an additional floatation tire with paddles mounted on an axleextension between the pairs of rear wheels. Thus, when the rear wheelsare driven, the paddles propel the modified ATV through a body of water.

U.S. Pat. Nos. 2,010,617 and 2,657,947 both show arrangements in which arail wheel is combined with a rubber tire of a vehicle so that thevehicle may travel on both a highway and a railway. In both structures,the rubber tire is attached directly against the rail wheel and therubber tire has a larger outside diameter than the rail wheel. In U.S.Pat. No. 2,010,617, the rubber tires are placed outwardly with respectto the rails. In U.S. Pat. No. 2,657,947, the rail wheels are locatedoutwardly with respect to the rubber tires. Thus, the rubber tires arelocated between the two rails when the vehicle including this wheelstructure is traveling on a railway. In both the structures described inthe two patents, the spacing between the rubber tires mounted on acommon axle must conform to the rail gauge. Therefore, adjustingvehicles with these wheel structures to different rail gauges isextremely complicated. Accordingly, each vehicle not originallymanufactured for railway use and employing these two kinds of wheelsrequires special and expensive modification.

As shown by the prior art, there is clearly a need for a lightweight andinexpensive vehicle that can travel on both railways and land, and thatcan be easily removed from and replaced on a railway, even at locationsremote from a grade crossing.

It is further desirable that such a vehicle can be readily modified foruse with railways of different gauges and, if necessary, between landand rail use.

In meeting these needs, the invention provides a four-wheelself-propelled vehicle with vehicle wheels and rubber tires fortraveling on land or a road and with rail wheels detachably mounted to,spaced from, and located outwardly of each of the vehicle wheels andhaving a gauge matching the gauge of a railway upon which the vehiclemay travel.

The lightweight vehicle is readily placed on and removed from a railroadeither at a grade crossing or at a location remote from a gradecrossing.

In further meeting the need, the invention provides a kit for modifyinga commercially available rubber-tired four-wheel vehicle. The kitprovides a coupling assembly including a vehicle wheel adapter formounting on the hubs of the vehicle that carry the wheels with rubbertires, and a rail wheel adapter for mounting on a rail wheel. Thecoupling assembly provides for coupling of the rail wheel and thevehicle wheel adapter, extending from the hub to a rail wheel. Byproviding a coupling arrangement of adjustable length, the vehicleincluding the rail wheels can easily be adjusted to operate on railroadshaving different rail gauges.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a self-propelled four-wheelvehicle for travel on land and on rails comprises four hubs for mountingof respective wheels including tires for travel of the vehicle on land,four rail wheels for traveling of the vehicle on rails of a railway, andfour coupling assemblies, each coupling assembly respectively detachablyconnecting one of the rail wheels to, outwardly of, and spaced from, thecorresponding hub.

A kit for detachably mounting rail wheels on hubs of a land vehicle forconverting the land vehicle for travel on rails comprises a rail wheeladapter including a flange for fastening to a rail wheel and an axleportion extending transverse to the flange, a vehicle wheel adapterincluding a flange for fastening to a hub of a land vehicle and an axleportion extending transverse to the flange, and coupling means forcoupling the axle portion of the rail wheel adapter to the axle portionof the vehicle wheel adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vehicle according to the invention;

FIG. 2 is a detail view of a rail wheel connected to a hub of a vehicleaccording to the invention and on which a rubber tire is mounted;

FIG. 3 is an exploded view of parts of a kit in accordance with theinvention in combination with a vehicle wheel and a rail wheel;

FIG. 4 is a detail, perspective view of a rail wheel on which part of akit according to the invention has been mounted;

FIGS. 5A and 5B are detail views of an alternative embodiment of partsof a kit according to the invention;

FIG. 6 is an exploded view of an alternative embodiment of a kitaccording to the invention;

FIGS. 7A and 7B are an exploded view and a partial, cross-sectional viewof parts of a kit according to the invention; and

FIG. 8 is a perspective view of still another embodiment of theinvention including a simplified electrical insulating arrangement.

In all figures, like elements are given the same reference numbers.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is perspective view of a vehicle 1 according to the invention.The basic vehicle shown is an example of a commercially availablegasoline-powered self-propelled ATV intended for a single rider.However, the invention encompasses other similar four-wheeled ATV andutility vehicles that accommodate two or more persons and that includespace for carrying some cargo. The vehicle includes a steering mechanismthat, in the illustrated embodiment, includes handlebars 3, for steeringtwo of the four wheels 4 of the vehicle 1. In a conventional way, thehandlebars control the angle of the front wheels. The rear wheels arenot steered. As shown in FIG. 1, the tires 6 are mounted on each of thefront and rear wheels 4, including the rear wheel that is not visible inFIG. 1. In addition, a rail wheel 7 is mounted on each of the hubs 9(not visible in FIG. 1) of the axles of the vehicle. The front and rearwheels 4 are also mounted on the respective hubs 9. The wheels 4 and thetires 6 are not essential to a land vehicle converted to railway useonly. Many of the converting structures depicted here show the wheels 4and the tires 6. However, it should be understood that the wheels andtires are not essential to the invention. A vehicle according to theinvention may have only rail wheels. Such a vehicle can travel on land,or at least on a hard surface on land, although not as efficiently aswhen running on rubber tires.

In the illustrated embodiment, the tires 6 have a larger outsidediameter than the rail wheels 7. Therefore, the vehicle can travel overland that is relatively smooth or a road with both the rail wheels 7 andthe tires 6 attached to the vehicle. When the vehicle is traveling onrails, care must be exercised at grade crossings when the rail wheels 7may be lifted from the rails by contact of the tires 6 with the road atthe grade crossing. Likewise, switches or other railway appliancesbetween rails may be contacted by the tires 6, and may lift the vehicleand the rail wheels 7 may move out of contact with the rails. When thevehicle is used on rails and is at a location remote from a gradecrossing, this relationship between the size of the tires and the railwheels may be exploited in easily removing the vehicle from the rails.For example, ramps may be placed between the rails so that the tiresclimb the ramps, lifting and disengaging the rail wheels from the rails,thereby facilitating removal of the vehicle from the rails. The sameramps can be employed in reverse, in returning the vehicle to the railsat a remote location. At a grade crossing, the vehicle can be easilyplaced on wheels simply by aligning the rail wheels with the rails anddriving off the end of the grade crossing at the level of theintersecting road. The vehicle is derailed at a grade crossing inexactly the reverse procedure. Further, if the vehicle should derail,the tires provide support to the vehicle so it does not plunge betweenthe rails and function as a guardrail to prevent the vehicle fromleaving the rail roadbed while the vehicle is brought to a stop. Thevehicle's sideward motion is limited because the rail is between thetire and the rail wheel.

It is apparent from FIG. 1 that the vehicle, when mounted on rails, ispropelled by the same propulsion system that drives the wheels of thevehicle. Since the rail wheels 7 are directly fastened to the drivenwheels of the vehicle there is no need to establish or maintain contactbetween the rails and the tires or to modify the spacing between thetires to propel the vehicle.

FIG. 2 is a detail view showing, in a perspective view, one example of acoupling between a tire 6 and a rail wheel 7. In the illustratedexample, a coupling assembly includes a vehicle wheel adapter 10fastened to the hub 9 at the end of an axle of the vehicle, using theexisting studs 20 of the axle assembly of the vehicle and lug nuts 11.The vehicle wheel adapter 10 is fastened to a central coupler, an axleextension tube 12 that is part of the coupling assembly. The engagementis secured by a fastener, such as the bolt 13 and a nut, as describedbelow.

A more detailed view of the coupling assembly shown in the partialdetail view of FIG. 2 is shown in the exploded view of FIG. 3. Turningto that FIG. 3, the tire 6 is shown mounted on the vehicle wheel 4 that,in turn, is mounted on the hub 9 of the axle. The studs 20 protrude fromthe hub 9 through holes in the wheel and are conventionally used tomount the wheel 4. The adapter 10 includes a flange 15, transverse tothe axle and including openings for passage of the studs 20. The vehiclewheel adapter 10 is fastened to the hub 9 with the same lug nuts 11 usedto mount the wheel 4. The vehicle wheel adapter 10 includes an axleportion, a shaft 21 extending transverse to the flange 15, that isreceived within the central coupler, the axle extension tube 12. Theshaft 21 includes a hole that may be aligned with a similar hole in theaxle extension tube 12 for passage of a bolt 13 that is secured with anut 23. The bolt-passing holes are transverse to the axis of rotation ofthe wheel 4.

At the opposite end of the axle extension tube 12, a shaft 24, as anaxle portion, protruding from a rail wheel adapter 25 is received withinthe axle extension tube. The shaft 24 is fixed within the axle extensiontube with a bolt 13 and a nut 23, for example, passing through alignableholes within the axle extension tube and the shaft 24 of the rail wheeladapter 25. These holes are transverse to the axis of rotation of thewheel 4. The rail wheel adapter 25 includes a flange 26 transverse tothe shaft 24. The flange 26 has a number of peripherally located holesthat align with corresponding holes in the rail wheel 7. The alignedholes receive fasteners, such as bolts 27 and nuts 28 securing the railwheel 7 to the rail wheel adapter 25. FIG. 4 shows this attachment in aperspective view.

The spacing between a pair of rail wheels 7 mounted on a front or rearaxle of the vehicle 1 have a separation that depends upon the spacingbetween the vehicle wheels and the length of the coupling assembly,i.e., the lengths of the adapters 10 and 25 and of the axle extensiontube 12 interposed between and coupling the adapters. Thus, the lengthsof these articles are chosen so that the width between the mounted railwheels 7 matches the gauge of a railway on which the vehicle is to beused. When the vehicle will be used on a single gauge railway, then itis desirable that, for the illustrated embodiment, that a single lengthcentral coupler, i.e., axle extension tube 12, be employed. However, bysupplying multiple sets of axle extension tubes 12 of different lengths,vehicles suitable for use on different gauge railways can easily beassembled.

In order to convert a vehicle from land use only to use both on land andon a railway, it is only necessary to supply a kit of couplingassemblies to provide the connection between railway wheels 7 and hubs 9of the land vehicle. In other words, a coupling assembly kit including avehicle wheel adapter, a rail wheel adapter, an axle extension tube, arail wheel, if needed, and fasteners for connecting these elements isall that is required to adapt each wheel of the vehicle for rail use.Although the fasteners illustrated in FIGS. 3 and 4 are all nuts andbolts, this illustration is not intended to exclude the use of otherkinds of fasteners that provide sufficient shearing strength fortransmitting the necessary torque between the vehicle wheels and therail wheels. It is particularly useful in this embodiment and theembodiments described below to use fasteners that may quickly bereleased, such as pins held in place by cotter pins, for rapidattachment and detachment of rail wheels, provided strength and safetyof the coupling is not impaired. As shown in the figures, if the vehicleis to be converted from land use to rail use exclusively by removing thetires and associated wheels, then a further adjustment or shim isneeded. As shown in the drawings, when the wheel 4 with the tire 6 ismounted on the hub, part of the wheel is interposed between the hub andthe vehicle wheel adapter. The distance between the rail wheels may bedetermined on this basis. However, if the vehicle wheel and tire areremoved, the pair of rail wheels on one axle will move closer togetherby twice the thickness of one of the vehicle wheels. To maintain thecorrect rail gauge, either the coupling assemblies must be designed toaccount for this change in distance or shims must be installed betweenthe hubs and the vehicle wheel adapters in place of the vehicle wheels.

FIGS. 5A and 5B illustrate modifications of the axle extension tube 12and the shaft 24 of the rail wheel adapter. As shown in FIG. 5A, theinternal surface of the axle extension tube may include a spline 30 andthe shaft 24 of the rail wheel adapter may include a complementarygroove 31 for receiving the spline 30. The complementary groove andspline arrangement, which can be reversed as shown in FIG. 5B, providesimproved torque transmission between the hub 9 and the rail wheel 7 ascompared to the sole use of nuts and bolts, pins, or similar fasteners.It is also desirable to provide a spline groove on the shaft 21 of thevehicle wheel adapter 10, although that groove is not illustrated inFIG. 5A. FIG. 5B shows a complementary spline and groove arrangementwhen the coupling assembly includes a tubular rail wheel adapter andshaft on the vehicle wheel adapter as in the embodiments describedbelow. Of course, the use of the spline and groove is only a singleexample of a structure that can be used to increase the engagement areaof the parts of the coupling assembly that are fastened together. Theinvention encompasses other interlocking complementary structuresintended to withstand shear forces and to transmit torque as the railwheel is driven by rotation of the vehicle wheel.

In the embodiment described with respect to FIG. 3, each of the adaptersof the coupling assembly includes an axle portion, a protruding shaftthat is received within a central coupler, the tubular axle extensiontube. However, this arrangement is not exclusive and the couplerassembly of the invention encompasses equivalent structures in whichparts of the adapters are received within and secured to a centralcoupler and in which the adapters include tubular portions receiving ashaft located centrally between the two adapters, as in FIG. 5B.Further, as illustrated by embodiments described below, the centralcoupler can include a tubular portion at one end and a shaft at anopposite end coupled to complementary elements on the respective vehiclewheel and rail wheel adapters. As illustrated in FIG. 3, couplerassemblies according to the invention include the two separate adapters,one for the vehicle wheel and one for the rail wheel, connected to eachother, either directly or with a central coupler disposed between,engaging, and fastened to the adapters.

When the vehicle including the rail wheels is operating on rails, thereis no necessity of steering the vehicle with the handlebars 3 orwhatever other steering device is provided. In fact, it is desirable, inorder to avoid unintended derailing, to lock the steering device so thatthe steered wheels of the vehicle follow the path of the rails. Thelocking mechanism can be quite simple and include a strap connectedbetween the body of the vehicle and the handlebars 3 or another steeringcontrol. Alternatively, a hinged fork can be attached to the body of thevehicle and merely pivoted into place, over the handlebars 3, or throughanother kind of steering device, such as a steering wheel, to preventundue movement of the steering device. Further, one or more pins may beinserted into holes in a plate attached to a steering column andengaging or passing through a steering device, such as the handlebars 3,to lock the steering mechanism in place against turning by other thanthe rails on which the vehicle is traveling.

Although the illustrated vehicle includes tires that are larger indiameter than the rail wheels, the invention may encompass a vehicle inwhich the rail wheels are larger in diameter than the tires. In thatevent, the vehicle must be raised, for example by driving the vehicle upramps, so that the rail wheels can be installed. Moreover, the railwheels have to be removed before the vehicle is suitable for operatingon a road or over land. While the attachment and removal of the railwheels can be relatively simple, since the vehicle wheel adapters canremain in place even after the rail wheels have been removed, it isstill preferred that the tires of the vehicle be larger in diameter thanthe rail wheels for travel on land.

FIG. 6 illustrates an alternative coupler assembly for connecting therail wheel 7 to the hub 9. This embodiment includes fewer parts than theembodiment illustrated in FIG. 3. Therefore, the kit for this couplerhas fewer parts and is cheaper to manufacture. The embodiment of FIG. 6includes a vehicle wheel adapter 40 having a flange 41 with a pluralityof holes for alignment with the studs 20 of the vehicle hub 9. The studs20 pass through corresponding holes of the flange 41 and lug nuts 11 areemployed to fasten the vehicle wheel adapter 40 to the hub 9. Thevehicle wheel adapter 40 includes a shaft 42 as an axle portion thatextends into and engages a rail wheel adapter 44. The rail wheel adapter44 includes a transverse flange 45 including holes that align withcorresponding holes in the rail wheel 7. The rail wheel adapter 44 has agenerally tubular protrusion 46, transverse to the flange 45, as an axleportion, and receives within a central opening the shaft 42 of thevehicle wheel adapter 40. Holes within the rail wheel adapter 44 and theshaft 43 and transverse to the axis of rotation of wheels are aligned sothat the two adapters 40 and 44 are joined together by a fastener, suchas the bolt 13 and the nut 23. An important feature of this embodimentis the tubular structure 46 of the rail wheel adapter 44 so that theshaft 43 of the vehicle wheel adapter can pass completely through therail wheel adapter 44 and a central hole within the rail wheel 7.Although the depicted embodiment shows only a single transverse hole inthe shaft 42, multiple holes can be provided along the shaft 42 so thatthe position of the rail wheel adapter 44 relative to the shaft 42 canbe fixed at any one of several selectable positions. In that way, thedistance between a pair of rail wheels at the front and back of thevehicle can be changed to easily accommodate different gauge railways.As in FIG. 3, the kit in FIG. 6, including the adapters 40 and 44 isshown as employing nuts and bolts as fasteners. Alternative fastenerscan be employed. In addition, a structure providing improved torquetransmission, such as the spline and complementary groove shown in FIGS.5A and 5B, can be employed with the shaft 42 and the rail wheel adapter44 of FIG. 6.

In the embodiment of FIG. 6, the vehicle wheel adapter 40 includes aprotruding shaft and the rail wheel adapter has a protruding, at leastpartially tubular, portion 46 for receiving the shaft. Thiscomplementary engaging structure can, within the scope of the invention,be reversed, with the rail wheel adapter having a shaft received withina tubular vehicle wheel adapter to couple the vehicle and rail wheels.

The embodiments of the invention described above all work satisfactorilyin achieving their purpose. However, in the previously describedembodiments, the hubs 9 are in electrical contact with the attached railwheel 7. In a vehicle in which the wheels on a front or rear axleassembly are in electrical communication, the attached rail wheelsaccording to the invention will be in electrical communication. In manyrailways, an approaching rail car at a grade crossing, triggeringwarning signals and/or gates for road traffic, is detected by sensingestablishment of an electrically conducting path between the rails. Inother words, an approaching train establishes an electrical currentbetween the rails. The flow of the current triggers the signals and/orgates at the grade crossing. It is not desirable or necessary for avehicle according to the invention to trigger these signals since thevehicle, unlike a train, can slow down near a grade crossing and stoprelatively quickly to wait for road traffic to clear.

To avoid triggering traffic signals, it is necessary to electricallyinsulate the rail wheels 7 from the hubs 9. An assembly achieving thatresult is illustrated in FIGS. 7A and 7B. FIG. 7A shows a part of theembodiment of the structure illustrated in the exploded view of FIG. 6.FIG. 7B is a cross-sectional view of the parts illustrated in FIG. 7A,after assembly. The parts like numbered shown in FIGS. 7A and 7B are thesame as those shown in FIG. 6. In addition, an electrically insulatingdisk 50, which may be a plastic or other somewhat rigid electricallyinsulating material that can tolerate the environmental conditionsproduced by the vehicle, is interposed between the vehicle wheel adapterflange 41 and the hub 9. The disk 50 includes holes matching the studs20 extending from the hub 9 on which the wheel 6 is mounted. The disk 50provides electrical insulation between the hub 9 and the flange 41 ofthat vehicle wheel adapter 40. To complete the desired electricalisolation, it is necessary that the nuts 42 not come in direct contactwith the flange 41. To achieve that end, insulating bushings 51 areinserted within each of the holes in the flange 41, electricallyinsulating the studs 20 from the flange 41. The bushings 51 includecollars on which the nuts 11 bear when the nuts are tightened, ensuringelectrical insulation as illustrated in FIG. 7B. Even if the structures,i.e., shaft and tube, of the vehicle wheel adapter and rail wheeladapter are interchanged, the same electrically insulating disk andbushings can be used to achieve the same goal. Likewise, the insulatingmembers, i.e., disk and bushings, can be provided at the rail wheel andrail wheel adapter to produce the same result.

Another electrical insulation arrangement is illustrated in FIG. 8. Forsimplicity, in FIG. 8 the rail wheel 7 is not illustrated. The apparatusof FIG. 8 includes a vehicle wheel adapter 60 having a flange 61 withholes located for passage of the studs 20 extending from the hub 9. Asin the apparatus of FIG. 6, the vehicle wheel adapter 60 is mounted onthe hub 9 using lug nuts 11 engaging the studs 20 passing through therespective holes of the flange 61. The vehicle wheel adapter 60 alsoincludes an extending tubular portion 62 that receives an insulatedshaft 63 of a rail wheel adapter 64. The rail wheel adapter includes aflange 65 for bolting to the rail wheel 7 in the manner alreadydescribed with respect to FIG. 6. The insulated shaft 63 extendsperpendicular to the flange 65 and includes an electrically insulatingsleeve 66 press-fit on a metal shaft 67. When the insulated shaft 63 isinserted within the tubular portion 62 of the vehicle wheel adapter,holes within and transverse to the tube and the shaft are aligned, abolt 13 is inserted through the aligned holes and is secured with a nut23. In order to insulate the bolt 13 from both the rail wheel adapter 64and the vehicle wheel adapter 60, the bolt 13 is inserted through anelectrically insulating bushing 67 that extends at least part waythrough the aligned holes in the tube 62 and the shaft 63. A bushing 51completes the electrical insulation. The bushing 51 has a collar onwhich the bolt 13 rests when the bolt 13 and the nut 23 are tightened.The bolt 13 controls the position of the metal shaft 67 within the tube62. Therefore, the end of the metal shaft 67 will not contact the hub 9or any other metal part. Accordingly, no insulating disk, like the disk50 of the embodiment of FIG. 6 is required in the embodiment of FIG. 8.The apparatus illustrated in FIG. 8 is simpler than the apparatusillustrated in FIG. 7A because it includes fewer parts and theelectrically insulating sleeve 66 can be permanently attached to therail wheel adapter 64.

The invention provides significant advantages over the prior art. Sincethe coupling assemblies include at least two principal members, thevehicle wheel adapter and the rail wheel adapter, the vehicle wheeladapter can be left in place, permanently, after the rail wheel and therail wheel adapter are removed. Then, the rail wheel and the rail wheeladapter can be added and removed, as needed, quickly. Moreover, the wayin which the two adapters couple to each other makes the conversionsimple and easily accomplished by only one person.

The invention has been described with respect to certain preferredembodiments. However, the scope of the invention is determined solely bythe following claims and encompasses not only the structures illustratedbut also all modifications and additions within the spirit of theinvention and equivalents thereof.

1. A self-propelled four-wheel vehicle for travel on land and on railscomprising: four hubs for mounting of respective wheels including tiresfor travel of the vehicle on land; four rail wheels for traveling of thevehicle on rails of a railway; and four coupling assemblies, eachcoupling assembly respectively detachably connecting one of the railwheels to, outwardly of, and spaced from, the corresponding hub.
 2. Thevehicle of claim 1 wherein at least two of the rail wheels areelectrically isolated from the respective hubs to which they areconnected by the respective coupling assemblies.
 3. The vehicle of claim1 wherein at least one of the coupling assemblies includes a vehiclewheel adapter having a flange fastened to one of the hubs and a railwheel adapter including a flange fastened to one of the rail wheels,wherein the vehicle wheel adapter and the rail wheel adapter includecomplementary protruding axle portions fastened to each other.
 4. Thevehicle of claim 3 including a central coupler interposed between andfastened to the vehicle wheel adapter and the rail wheel adapter.
 5. Thevehicle of claim 4 wherein at least one end of the central coupler andat least one of the axle portions of the vehicle wheel adapter and therail wheel adapter includes a spline and the other of the end of thecentral coupler and the at least one of the axle portions includes agroove complementary to and receiving the spline.
 6. The vehicle ofclaim 4 wherein the central coupler includes at least one tubular endand at least one of the vehicle wheel adapter and the rail wheel adapterincludes a protruding shaft as the axle portion protruding from therespective flange and received in and fastened to the tubular end of thecentral coupler.
 7. The vehicle according to claim 6 wherein one of thetubular ends of the central coupler and the shaft includes a spline andthe other of the tubular end and the shaft includes a spline groovecomplementary to and receiving the spline.
 8. The vehicle according toclaim 5 wherein each of the vehicle wheel adapter and the rail wheeladapter includes a respective shaft protruding from the respectiveflanges as an axle portion, and the central coupler is tubular andreceives and is fastened to the shafts of the vehicle wheel adapter andthe rail wheel adapter.
 9. The vehicle of claim 3 wherein one of thevehicle wheel adapter and the rail wheel adapter includes a shaft as anaxle portion and the other of the vehicle wheel adapter and the railwheel adapter is at least partially tubular and receives and is fastenedto the shaft.
 10. The vehicle of claim 3 wherein the vehicle wheeladapter includes the shaft.
 11. The vehicle of claim 10 including anelectrically insulating disk interposed between the flange of thevehicle wheel adapter and the hub to which the vehicle wheel adapter isfastened, electrically insulating the flange from the hub.
 12. A kit fordetachably mounting rail wheels on hubs of a land vehicle for convertingthe land vehicle for travel on rails, the kit comprising: a rail wheeladapter including a flange for fastening to a rail wheel and an axleportion extending transverse to the flange; a vehicle wheel adapterincluding a flange for fastening to a hub of a land vehicle and an axleportion extending transverse to the flange; and coupling means forcoupling the axle portion of the rail wheel adapter to the axle portionof the vehicle wheel adapter.
 13. The kit of claim 12 wherein one of theaxle portions of the rail wheel adapter and of the vehicle wheel adapteris a shaft and the other of the axle portions of the rail wheel adapterand the vehicle wheel adapter is a tube receiving the shaft and thecoupling means comprises fasteners for passing through the shaft and thetube when the rail wheel adapter is coupled to the vehicle wheeladapter.
 14. The kit of claim 13 wherein one of the shaft and the tubeincludes a spline and the other of the shaft and the tube includes agroove complementary to the spline, for receiving the spline when therail wheel adapter is coupled to the vehicle wheel adapter.
 15. The kitof claim 12 wherein each of the axle portions of the rail wheel adapterand the vehicle wheel adapter comprises a shaft and the coupling meanscomprises a tubular central coupling member for receiving in respectiveends the shafts of the rail wheel adapter and the vehicle wheel adapter,and fasteners for passing through the shafts and the central couplingmember when the rail wheel adapter is coupled to the vehicle wheeladapter.
 16. The kit of claim 15 wherein one of (i) the shafts of therail Wheel adapter and the vehicle wheel adapter and (ii) at least oneend of the central coupling member includes a spline and the other of(i) the shafts of the rail wheel adapter and the vehicle wheel adapterand (ii) at least one end of the central coupling member includes agroove complementary to the spline for receiving the spline when theshaft is coupled to the central coupling member.
 17. The kit of claim 12including an electrically insulating disk for interposition between ahub of the vehicle and the vehicle wheel adapter to electricallyinsulate the rail wheel adapter from the hub.
 18. The kit of claim 17wherein the coupling means includes fasteners and further includingelectrically insulating bushings for electrically insulating thefasteners from at least one of the rail wheel adapter and the vehiclewheel adapter.